Intra-pulpal temperature rises in power bleaching

Abstract

Objective To measure the surface and intra-pulpal temperature increases in vitro on upper and lower anterior teeth during tooth whitening procedures. Method A thermocouple was used to measure the temperature increase on the surface of an extracted upper central incisor tooth. Intra-pulpal temperature readings were made on upper and lower central incisors, lateral incisors and canines. Four lamps recommended for tooth bleaching were tested; a plasma arc lamp, a xenon-halogen lamp, a standard halogen lamp and a diode laser lamp. Temperature measurements were made with and without the bleaching agent present on the labial tooth surface. Results The increase in surface temperature readings ranged from 0.44°C (luma arc) to 86.3°C (laser) with no bleaching gel present. Intra-pulpal temperature increases ranged from 0.30°C to 15.96°C. The presence of the bleaching gel reduced temperature increases seen at the tooth surface and within the pulp. Conclusions The increase in the intrapulpal temperature with most bleaching lamps was below the critical threshold of a 5.50°C increase thought to produce irreversible pulpal damage. The only lamp that produced an intrapulpal temperature increase above this threshold was the laser-based lamp and caution is advised when using this equipment.